Subject: Re: CCL:Paking in the unit cell

From: <[email-masked]>
Date: Fri, 20 Jun 1997 14:50:29 -0500

Alexandre N. Sobolev wrote:
> 
> >
> > Hi
> >    Along these same lines, I am seeking a program that will allow 
> > one to
> > build a lattice of molecules by inputting one or several different
> > molecular files as well as the unit cell dimensions.  I currently 
> > have a
> > routine called bcell that will make a lattice of multiple copies of 
> > the
> > SAME molecule file, but I need a routine that will allow a lattice 
> > to be
> > built which will contain multiple copies of one molecule in the 
> > lattice,
> > as well as ONE that is different.
> >
> >   Anyone have any suggestions?
> >
> > Richard

Hi-
    Let me clarify what I need as I think there may be a
misunderstanding here.  I am attempting to build a mono/bilayer of
phospholipids for an MD simulation.  I wish to have 16/32 copies of the
same molecule aligned in space using the unit cell dimensions of a
single crystal.  What I want to do is selectively introduce a double
bond in ONE of the phospholipids.  Thus, I want 15/31 saturated lipids
and 1 unsaturated lipid.  The routine that I have will allow me to
assemble multiple copies of ONE file, not two, which is what I need.
I used a program called Chemlab to build my original lipid, and i sue it
to introduce the unsaturation in my lipid, but I cannot use it to edit a
mono/bilayer, as it only handles 999 atoms.  I can't modify Chemlab as
we don't have access to the code.

Any suggestions?

Richard